In the evolution of automobiles from motorized carriages to highly regulated devices for mass transportation, there has been a continuous pursuit of refinement of the basic combination of elements that comprise the automobile. One aspect of this refinement has been the transmission of torque from the engine to the drive system of the vehicle. This transmission of torque has, throughout, been accomplished by various gear or chain driven transmission systems alternatively drivingly connected to, or disconnected from, a source of motive power. The connection/disconnection feature of the drive system is accomplished by means of a clutch. Since the mid-1950's, especially in the United States, this clutch has been a fluid clutch or torque converter. Owing to the inclusion of this fluid torque transmitting coupling, enhanced refinement of the driving experience was obtained, but this refinement came at the expense of lost efficiency. To address this lost efficiency, the torque converter has become, itself, an object of greater refinement and recaptured efficiency. Often times, a modern era torque converter will include a friction clutch assembly associated with a driven member of the torque converter which, at preset loads and speeds, eliminates the fluid transmission of torque and replaces the fluid coupling with a direct mechanical friction coupling. This feature is commonly referred to as a lock-up clutch.
In the era of the lock-up clutch-equipped torque converter, efficiency has been recaptured, but a loss of refinement has also occurred when the clutch is in lock-up mode and when it is transitioning into and out of lock-up mode. This is especially true when the lock-up clutch elements become worn and tolerances between various rotating and fixed elements increase/decrease in accord with their respective wear patterns. To alleviate some of the mechanical coarseness created by the incorporation of lock-up clutches onto torque converters, the clutch systems, themselves, have increased in complexity. For example, the inclusion of a driven intermediate plate, and the further inclusion of elastic damping members, to keep driveline torque oscillations within acceptable parameters, adds rotational mass and complexity to the torque converter sub-assemblies. This added complexity creates the potential for a loss of refinement through vibration caused, in part, by unbalanced decentered rotation of the various components. In addition, it is common for the elastic torque transmitting member equipped devices to, over time and with use, develop rattles and other noises that create a perception of low integrity of the torque converter device. In addition, the assembly of these increasingly complex clutch and damper systems requires more time, patience, and precision. Examples of such torque converters equipped with a lock-up clutch and elastic torque transmission element through an intermediate plate are shown in U.S. Pat. Nos. 8,453,439; 8,025,136; and, U.S. Pat. No. 6,938,744, for example.
While conventional hydrokinetic torque-coupling devices, including but not limited to those discussed above, have proven to be acceptable for vehicular driveline applications and conditions, improvements that may enhance their performance and cost are possible.